Fire Strategy Requirements for Residential Developments

Fire Strategy Requirements for Residential Developments

Residential buildings encompass one of the widest ranges of building types in the UK construction sector — from small terraced houses and modest conversions to large purpose-built blocks of flats and build-to-rent towers. Fire strategy requirements vary significantly across this range, driven by building height, occupancy density, and whether the building falls within the scope of the Building Safety Act 2022 as a higher-risk building.

The Applicable Standards

The primary standard for fire strategies in residential buildings is BS 9991:2015 — Fire Safety in the Design, Management and Use of Residential Buildings. BS 9991 covers a wide range of residential building types and provides guidance on means of escape, compartmentation, sprinklers, smoke control, and firefighting facilities for each. It is supplemented by Approved Document B and, for higher-risk buildings, by the Building Safety Regulator's requirements under the Building Safety Act 2022.

Key provisions of BS 9991 that affect residential fire strategy design include:

• Sprinkler requirement — BS 9991 requires sprinkler systems in all new residential buildings in England over 11 metres in height. Wales has a lower threshold of 6 metres for residential buildings with more than two storeys above ground floor.
• Stay-put evacuation — the standard evacuation strategy for purpose-built blocks of flats, relying on robust compartmentation to contain fire within the flat of origin
• Corridor length limits — maximum travel distances in protected corridors to escape staircases, varying with the configuration of the escape route
• Fire resistance periods — 30 minutes for buildings up to 11 metres; 60 minutes for buildings over 18 metres

Houses and Low-Rise Residential Buildings

For simple houses and low-rise residential buildings, compliance with Approved Document B is typically achievable using standard prescriptive guidance without a specialist fire strategy. However, where houses are converted to flats or houses in multiple occupation (HMOs), or where non-standard configurations are proposed, a fire strategy may be needed to demonstrate compliance.

For HMOs — houses with multiple occupants who are not members of the same family — the fire safety requirements are more stringent than for standard houses. Protected means of escape, fire detection throughout, and fire doors to each bedroom and habitable room are typically required, and a fire risk assessment is required under the RRO 2005 for HMOs with five or more occupants.

Purpose-Built Blocks of Flats

Purpose-built blocks of flats are the most common residential building type requiring a specialist fire strategy. The key fire safety design decisions for a block of flats are: the evacuation strategy (stay put or simultaneous evacuation); the number and configuration of escape staircases; the fire resistance specification for compartment walls and floors; the fire detection and alarm strategy for common areas; and whether sprinklers are required.

Build-to-Rent and Large Residential Schemes

Large build-to-rent and private rented sector residential schemes — often comprising hundreds of units across multiple buildings on a single site — require particular attention to fire strategy in terms of phasing, the relationship between buildings, and the management of residents who may have limited knowledge of the building layout. Fire strategies for these schemes must address the full site, not just individual buildings, and must consider how fire safety management will operate during and after phasing.